Prosecutors said McCarthy killed the toddler and then put her body in a trash bag and dumped her in the water off south Boston. The child’s mother, Rachelle Bond, pleaded guilty earlier this year to being an accessory after the fact and became the prosecution’s star witness.

She told jurors earlier this month that McCarthy killed her daughter because she didn’t want to go to sleep. “It was her time to die. She was a demon,” McCarthy said, according to Bond’s testimony.

Prosecutor David Deakin said the mother acted “inexcusably,” in keeping quiet about the killing, but said there was no evidence that Bond was a bad mother.

McCarthy’s lawyer called the mother’s testimony “a web of lies” and “unbelievable.”

As part of her plea deal, Bond was sentenced to time served and two years of probation, authorities said.